Let's talk about something that bricking and unbricking this device...
I've got a Zenfone 5Z (ZS620KL) at version 188.8.131.52 and want to unlock the bootloader but get a error while using official unlock app.
And I found some article saying that it will only work at older version e.g. 184.108.40.206.
Thus, I tried to downgrade to version 220.127.116.11 and follow the guide from here.
Guess what? I totally bricked this device and get black screen, with vol down + power button get vibrate only.
So, I went to ASUS official repair store and they want charge me about USD $300 to replace the motherboard, but I said no and told them I will try to revive this device by myself.
I made a special USB TYPE-C cable (as xiaomi edl usb cable) to let device boot into Qualcomm 9008 mode and follow this guide to revive this device.
https://www.firmware27.com/2018/05/f...s-zs620kl.html (Draco_ZS620KL_QMSCT_download.pdf (Tutorial Flashing))
Here is the detail that unbricking this device
1. Download "WW_ZS620KL_18.104.22.168_MR2_20180921002943_releas e-user.raw.zip"
2. Download "CSC-ZS620KL-80.02.237.70-FAC-eng-20180810191100-factory.zip"
3. Unzip "WW_ZS620KL_22.214.171.124_MR2_20180921002943_releas e-user.raw.zip"
4. Install python 2.7
5. Goto directory /WW_ZS620KL_126.96.36.199_MR2_20180921002943_release-user.raw/factory_for_QMSCT
6. Execute "unparse_img.bat"
7. Extract "fs_image.tar.gz.mbn.img" from "CSC-ZS620KL-80.02.237.70-FAC-eng-20180810191100-factory.zip" to "WW_ZS620KL_188.8.131.52_MR2_20180921002943_releas e-user.raw" folder
8. Run QMSCT and follow the steps in "Draco_ZS620KL_QMSCT_download.pdf"
9. If success, hold vold down + power button to reboot, it will show the splash screen
10. Reboot to bootloader and use AFT v184.108.40.206 to flash "WW_ZS620KL_220.127.116.11_MR2_20180921002943_releas e-user.raw.zip" again
11. Reboot and get a fully functional device back
Conclusion: DO NOT DOWNGRADE TO 18.104.22.168 TO PREVENT THIS